This invention relates to absorbent pads that are worn against the body, such as sanitary napkins. More particularly, this invention relates to an absorbent pad having a facing sheet with a fractional-denier fibrous nonwoven surface facing the wearer's body.
Absorbent pads that are worn against the body for absorbing bodily fluids, such as sanitary napkins, disposable diapers, and surgical dressings, typically have an absorbent core, such as fluffed cellulose batting, surrounded by a cover sheet. The cover sheet maintains the integrity and shape of the pad, and typically includes a backsheet on the side away from the wearer that prevents escape of the fluids being absorbed by the core and a facing sheet or topsheet on the side facing the wearer.
The backsheet must be impervious to bodily fluids to prevent the escape of fluids if, e.g., the absorbent core becomes saturated or pressure is exerted on the core. Backsheets are thus typically sheets of plastic such as polyethylene or other polyolefins, although it is possible to provide a backsheet of a fibrous fabric--either woven or nonwoven--that is treated to make it impermeable.
The facing sheet must be permeable to whatever fluid is to be absorbed by the pad. Originally, such facing sheets were made from large-fiber (i.e., from about 1.0 to about 9.0 denier, and typically from about 1.0 to about 3.0 denier) nonwoven natural or synthetic fibers, and at one time even woven sheets were used, but such facing sheets can allow the fluid to escape back out of the pad, and onto the wearer's skin or clothing, if, e.g., the absorbent core becomes saturated or pressure is placed on the core.
More recently, cast thermoplastic facing sheets have been provided. The sheets--e.g., of polyethylene film--are perforated to allow the bodily fluids to enter the pad, but the perforations are said to be designed to trap the fluids in the pad. However, such thermoplastic sheets do not allow the wearer's skin to breathe, so that they allow the buildup of moisture from sweat, causing a clammy feeling or other discomfort or irritation. Therefore, it is known to give such thermoplastic facing sheets a textured or dimpled surface, forming a less film-like fabric, to reduce the surface area that touches the skin and thereby to reduce the clamminess and irritation. Nevertheless, such sheets are not as comfortable against the wearer's skin as a fibrous facing sheet.
It would be desirable to be able to provide a fibrous nonwoven facing sheet for a pad for absorbing bodily fluids that lacks the disadvantages of both large-fiber nonwoven fibrous sheets and non-fibrous thermoplastic sheets.